Korean reactors cleared for restart

Three South Korean nuclear power reactors forced to stop operations in May 2013 after finding safety-related control cabling had falsified documentation have been given approval to restart.

Shin Kori units 1 and 2 (Image: KHNP)

With the cabling having been replaced, Korea's Nuclear Safety and Security Commission (NSSC) has now given Korea Hydro and Nuclear Power (KHNP) approval to restart operations at Shin Kori units 1 and 2 and Shin Wolsong unit 1.

Korean authorities began an investigation into safety certificates for the cabling in April 2013 after a tip-off. The following month, the NSSC ordered the units to shut. In the event of an accident, the cables send signals from the reactor operating systems, such as cooling, to the control room.

The newly-constructed Shin Wolsong 2 is having its cabling replaced and still awaiting approval to start commercial operation for the first time.

The discovery of falsified quality documentation for the cabling was said to be unrelated to the similar case announced in November 2012 in which KHNP had allegedly been supplied with falsely-certified non-safety-critical parts for at least five of the country's 23 power reactors.

The two most affected units, Yonggwang 5 and 6 (since renamed Hanbit 5 and 6), were taken off line for the parts to be replaced. The other affected units, Yonngwang (Hanbit) 3 and 4 and Ulchin (now Hanul) 3, were able to continue in operation during replacement work.

With several of its reactors off line for maintenance as well as those sidelined because of the data falsification issues, South Korea had found itself struggling to meet electricity during peak summer and winter demand. Nuclear provides one-third of the country's electricity.